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Medical research on noroxin
Jpn J Infect Dis. 2008 Nov; 61(6): 454-6
Funahashi K, Nakane K, Yasuda N, Suzuki M, Narita A, Arai N, Ahn J, Koyama N, Ushida H, Nishimura N, Ozaki T
Group A streptococcus (GAS) is a major cause of pediatric pharyngotonsillitis. In this study we determined the T serotype and antimicrobial susceptibility of GAS isolates from Japanese children. From January to December 2006, a total of 438 isolates of GAS were obtained from pharyngeal swabs of 438 children with pharyngotonsillitis. The commonest T serotype was type 1 (110 strains, 25.1%), followed by type 12 (107, 24.4%) and type 4 (77, 17.6%). All GAS isolated from pharyngeal swabs were susceptible to beta-lactams (benzylpenicillin, amoxicillin, cefotaxime, ceftriaxone, imipenem, panipenem, and cefditoren) and vancomycin, but 19.6, 19.6, 3.2, 11.6, and 27.6% were resistant to erythromycin, clarithromycin, clindamycin, minocycline, and norfloxacin, respectively. Resistance varied considerably with the T serotype. In particular, type 4 isolates had the highest resistance (67.5, 67.5, 26.0, and 53.2% were resistant to erythromycin, clarithromycin, minocycline, and norfloxacin, respectively).
J Microbiol Biotechnol. 2008 Nov; 18(11): 1853-1857
Lee K, Lee M, Lim J, Jung J, Park Y, Lee Y
Salmonella contamination in chicken meat was studied with 100 chicken meat samples purchased from 55 shops located in various regions. A total of 21 isolates of Salmonella enterica were isolated from 21 chicken meat samples from four shops located at open markets, whereas there were none from supermarkets with well-equipped cold systems. Among these, 18 isolates were identified as Salmonella enterica serotype Haardt (S. Haardt) and three isolates were S. enterica serotype Muenchen. When the minimal inhibitory concentrations of the S. Haardt isolates were assayed with the agar dilution method to determine susceptibility to ampicillin, chloramphenicol, sulfisoxazole, tetracycline, and nalidixic acid, all 18 isolates were resistant to tetracycline and nalidixic acid and nine of these were resistant to ampicillin. These isolates showed reduced susceptibility to eight fluoroquinolones including ciprofloxacin, enrofloxacin, levofloxacin, gatifloxacin, gemifloxacin, moxifloxacin, norfloxacin, and ofloxacin. When quinolone resistance determining regions of gyrA and gyrB were sequenced, every isolate had the same missense mutation Ser83-->Tyr (TCC-->TAC) in gyrA, whereas no mutation was found in gyrB. Pulsed-field gel electrophoresis with XbaI revealed a close relationship among these isolates, suggesting a contamination of raw chicken meat with clonal spread of nalidixic acid-resistant and quinolone-reduced susceptibility S. Haardt in chickens. Results in this study show the importance of a wellequipped cold system and the prudent use of fluoroquinolone in chickens to prevent the occurrence of quinolone resistant isolates.
Spectrochim Acta A Mol Biomol Spectrosc. 2008 Oct 28;
Nava-Júnior IS, Aucelio RQ
The selective determination of norfloxacin in mixtures with other fluorquinolones was achieved by synchronous scanning solid surface room-temperature phosphorimetry (SSRTP) and Th(NO(3))(4) as selective phosphorescence inducer. The method also allowed the determination of levofloxacin in a sequential way. The optimization of experimental conditions was made through an univariate approach, in order to find the best conditions for norfloxacin phosphorescence, followed by a 2(3) factorial design in order to verify interaction among relevant variables, to check robustness for each variable and to perform final adjustment of parameters. Absolute limit of detection (ALOD) for norfloxacin was 12ng with a linear signal response extending up to 400ng. Under the same experimental conditions set for norfloxacin, the ALOD for levofloxacin was 13ng with linear signal response up to 450ng. Accuracy of the method, using Th (IV) as selective phosphorescence inducer, was evaluated through the analysis of commercial and simulated pharmaceutical formulations with recoveries between 94.4 and 101% for norfloxacin and 95.9 and 103.8% for levofloxacin. The use of Cd (II), a traditional phosphorescence inducer for fluorquinolones, did not allow selective determination of norfloxacin. Further studies indicated the potential application of the method in urine samples.
Clin Microbiol Infect. 2008 Nov; 14(11): 1034-40
Bert F, Panhard X, Johnson J, Lecuyer H, Moreau R, Le Grand J, Johnston B, Sinègre M, Valla D, Nicolas-Chanoine MH
Spontaneous bacterial peritonitis (SBP) is a severe complication in patients with cirrhosis and ascites. It is predominantly caused by Escherichia coli. The phylogenetic group and virulence genotype of E. coli isolates causing SBP were investigated, and the association of these characteristics with host factors and prognosis was examined. Seventy-six episodes of E. coli SBP that occurred over a 9-year period were studied. The phylogenetic group of the isolates and the presence of 36 virulence factor genes were investigated. The influence of bacterial and host factors on in-hospital mortality was assessed by multiple logistic regression. Phylogenetic groups A, B1, B2 and D were found in 26%, 4%, 46% and 24% of the isolates, respectively. Virulence factor genes were more frequent in B2 isolates than in non-B2 isolates (mean virulence score 15.4 vs. 7.3, p
Anal Bioanal Chem. 2008 Nov 28;
Spangler C, Spangler CM, Spoerner M, Schäferling M
Guanine nucleotide binding proteins, such as Ras proteins, play a pivotal role in maintaining the regular life cycle of cells. The involvement of Ras mutants in the progress of cancer has attracted many efforts to find detection methods for Ras activity. In this study we present a luminescent microwell plate assay for monitoring GTPase activity of Ras proteins. The luminescence intensity of the Tb-norfloxacin complex is influenced by nucleoside phosphates as well as by inorganic phosphates. Real-time kinetics of the GTPase activity of wild-type Ras and Ras mutants can be monitored online. The effect of a GTPase activating protein as well as of a downstream effector (Ras-binding domain of human Raf-1) on the GTPase activity of different Ras mutants is examined. In contrast to other methods, this assay does not require the use of radioactively labeled substrates or chromatographic separation steps. Moreover, the application of fluorescently labeled GTP substrates which often interfere with enzymatic activity can be avoided. This in vitro assay can serve as a model system for the screening of regulators affecting the GTPase activity of Ras proteins.
CE determination of quinolones in the presence of bovine serum albumin.
J Sep Sci. 2008 Nov 26;
Qin W, Liu Q, Fan Y
This article describes the influence of bovine serum albumin (BSA) as an additive on the capillary electrophoresis-potential gradient determination of five quinolones, enoxacin, norfloxacin, ofloxacin, fleroxacin, and pazufloxacin. With 10 mg/L of BSA present in the buffer of 30 mM Tris and 3 mM phosphoric acid at pH 9, the detection limits of the five quinolones were in the range of 0.24-0.68 mg/L, i. e. 5.8-16.5-fold lower than those obtained with the buffer devoid of BSA, and the analysis time was shortened. We suggest that the inner wall-adsorbed BSA suppresses the adsorption of quinolones and simultaneously enhances the electroosmotic flow rate. Our experiments indicated that adopting the potential gradient detection technique could eliminate the interference of the UV-active proteins on the detection of quinolones that would occur with conventional optical detection, and therefore offer high detection sensitivity. As a demonstration, the method was applied to the determination of QNs in fortified chicken muscle sample with satisfactory results.
Antibiotic resistance patterns of pediatric community-acquired urinary infections.
Braz J Infect Dis. 2008 Aug; 12(4): 321-3
Guidoni EB, Berezin EN, Nigro S, Santiago NA, Benini V, Toporovski J
Knowledge about antimicrobial resistance patterns of the etiological agents of urinary tract infections (UTIs) is essential for appropriate therapy. Urinary isolates from symptomatic UTI cases attended at Santa Casa University Hospital of São Paulo from August 1986 to December 1989 and August 2004 to December 2005 were identified by conventional methods. Antimicrobial resistance testing was performed by Kirby Bauer's disc diffusion method. Among the 257 children, E. coli was found in 77%. A high prevalence of resistance was observed against ampicillin and TMP/SMX (55% and 51%). The antibiotic resistance rates for E. coli were: nitrofurantoin (6%), nalidixic acid (14%), 1st generation cephalosporin (13%), 3rd generation cephalosporins (5%), aminoglycosides (2%), norfloxacin (9%) and ciprofloxacin (4%). We found that E. coli was the predominant bacterial pathogen of community-acquired UTIs. We also detected increasing resistance to TMP/SMX among UTI pathogens in this population.
Jpn J Antibiot. 2008 Aug; 61(4): 195-208
, Kaeriyama M, Mizunaga S, Mitsuyama J, Yamaoka K, Asano Y, Sawamura H, Suematsu H, Teraji M, Tsuchiya M, Hashido H, Matsukawa Y, Matsubara S, Miyabe T, Watanabe K, Mikamo H
We investigated the susceptibility to antibacterials of 194 strains of Haemophilus influenzae isolated from medical facilities in Gifu prefecture between 2005 and 2006, and compared these results with those of 280 strains of H. influenzae isolated between 1999 and 2000. Additionally, the strains that had been separated between 2005 and 2006 were examined for beta-lactamase (BL) production, the mutation of ftsI gene coding for PBP3, the bla gene coding for TEM type of BL and the serotype. Referring to the CLSI breakpoint, H. influenzae strains were classified into the following categories: (1) beta-lactamase-negative ampicillin-susceptible (BLNAS) strains, which showed BL negative, ampicillin (ABPC) and ampicillin/sulbactam (ABPC/SBT)-MIC < or = microg/ml, (2) beta-lactamase producing ampicillin-resistant (BLPAR) strains, which showed BL producing and ABPC/SBT-MIC < or =2 microg/ml, (3) beta-lactamase-negative ampicillin-resistant (BLNAR) strains, which showed BL negative, ABPC and ABPC/SBT-MIC > or =2 microg/ml, (4) beta-lactamase-producing amoxicillin/clavulanic acid-resistant (BLPACR) strains, which showed BL producing and ABPC/SBT-MIC > or =4 microg/ml. The prevalence of each resistance class were 71.8% for BLNAS, 7.9% for BLPAR, 19.6% for BLNAR and 0.7% for BLPACR in strains isolated between 1999 and 2000. But they were 38.1% for BLNAS, 4.6% for BLPAR, 54.6% for BLNAR and 2.6% for BLPACR in strains isolated between 2005 and 2006, indicating that the percentage of BLNAS and BLPAR decreased and that of BLNAR and BLPACR increased from 1999-2000 to 2005-2006. On the basis of ftsI substitutions and having bla gene, the strains isolated between 2005 and 2006 were classified into the following distribution: 24.2% for gBLNAS, 4.1% for gBLPAR, 10.8% for gLow-BLNAR, 57.7% for gBLNAR, and 3.1% for gBLPACR-II. Ratio of BLNAR belonging to gBLNAR and gLow-BLNAR based on the ftsI substitutions and having bla gene was higher than that based on the susceptibility pattern. The MIC50 and MIC90 for those strains isolated between 2005 and 2006 were as follows; 0.0039, 0.0156 microg/ml for garenoxacin, 0.0078, 0.0156 microg/ml for tosufloxacin and ciprofloxacin, 0.0156, 0.0313 microg/ml for levofloxacin, 0.0313, 0.0625 microg/ml for norfloxacin, 0.0625, 0.25 microg/ml for piperacillin/ tazobactam, 0.0625, 0.5 microg/ml for piperacillin, 0.125, 0.25 microg/ml for ceftriaxone and cefditoren, 0.5, 1 microg/ml for cefteram, chloramphenicol and tetracycline, 0.5, 2 microg/ml for cefotaxime, 2, 8 microg/ml for ampicillin, ampicillin/sulbactam and cefdinir. In comparison with the values for the strains isolated between 1999 and 2000, the MIC50s of beta-lactam for the strains isolated between 2005 and 2006 increased over 4 times.
Int J Antimicrob Agents. 2008 Nov 14;
Neves FP, Ribeiro RL, Duarte RS, Teixeira LM, Merquior VL
We describe the characteristics of seven unusual isolates of vancomycin-resistant enterococci (VRE) carrying both the vanC1 and vanA genes that were detected during a 3-month survey carried out to investigate the occurrence of faecal carriage of VRE. The isolates were identified as Enterococcus gallinarum and showed high-level resistance to both vancomycin and teicoplanin (minimum inhibitory concentrations >256mug/mL and 64-96mug/mL, respectively). All seven isolates were also resistant to chloramphenicol, erythromycin and high levels of gentamicin, and showed intermediate susceptibility to both quinolones tested (ciprofloxacin and norfloxacin). Susceptibility to fosfomycin, rifampicin and tetracycline varied among isolates. High-level resistance to gentamicin was associated with the aac(6')-aph(2'') gene, and resistance to erythromycin was associated with the erm(B) gene. The seven vanA-carrying E. gallinarum isolates had similar pulsed-field gel electrophoresis (PFGE) profiles. The emergence of multiple antimicrobial resistance, including high-level resistance to glycopeptides, among E. gallinarum points out the need to increase awareness for detection and proper characterisation of these microorganisms, as they may represent potential reservoirs of transmissible, clinically significant resistance genes in nosocomial settings.
J Chromatogr A. 2008 Dec 19; 1214(1-2): 100-8
Xiao Y, Chang H, Jia A, Hu J
A sensitive liquid chromatography-electrospray tandem mass spectrometry method, combined with solid-phase extraction and a weak cation exchange cartridge cleanup, was established for twenty quinolone and fluoroquinolone antibiotics (pipemidic acid, flerofloxacin, ofloxacin, pefloxacin, enoxacin, norfloxacin, ciprofloxacin, danofloxacin, enrofloxacin, lomefloxacin, difloxacin, sarafloxacin, gatifloxacin, sparfloxacin, moxifloxacin, cinoxacin, oxolinic acid, nalidixic acid, flumequine, and piromidic acid) in influent, effluent, and river waters. For the various water matrices considered, the overall recoveries were from 64% to 127% except for piromidic acid (27-33%), and no obvious matrix effect was observed. The method detection limits for the twenty target antibiotics in the influent, effluent, and surface water samples were 1.6-50ng/L, 0.6-50ng/L, and 0.8-50ng/L, respectively. This method was applied to analyze residual quinolone and fluoroquinolone antibiotics in wastewater and surface water samples from Beijing, China. Eight antibiotics (12 (pipemidic acid)-1208ng/L (ofloxacin)) were detected in wastewater, and seven (1.3 (lomefloxacin)-535ng/L (ofloxacin)) were detected in surface water samples. Gatifloxacin, a 4th generation fluoroquinolone antibiotic, was detected for the first time in influent (111ng/L), effluent (56ng/L), and river water (16-42ng/L).